We are interested in the structure, evolution and expression of preproinsulin and preproinsulin-like genes. We are also interested in the genetic background of insulin-dependent diabetes mellitus. We propose to continue our past studies on the molecular characterization of preproinsulin genes by studying their expression in regulatiing cell lines, derived from insulin-producing cells. Except for possible studies on in vitro mutated cloned genes, we will attempt to identify regulatory proteins possibly present on recoverable "minichromosomes" that will be generated by microinjection of recombinants of bovine papilloma virus (which jdoes not integrate into the host genome) and preproinsulin genes. Our studies will be extended to examine the gene structure of other evolutionarily related members of the insulin protein superfamily, expecially the human growth factors IFG-I and IGF-II, which are under growth hormone control and probably the madiators of some of its actions. In parallel, we will initiate a study to examine at the molecular level the docmented assocation between HLA loci around the D/DR area and insulin-dependent diabetes mellitus. This DNA region will be characterized and compared in cloned chromosomal DNA from libraries of already haplotyped normal and diabetic individuals, by using initially as a marker a cloned gene encoding factor Bf of the alternative complement pathway (that is genetically linked to this HLA area) and then "walking on DNA". Though elucidation of the genetic background of this form of diabetes cannot be guaranteed, the project will definitely lead to the characterization of the linked genes encoding Bf and the complement components C2 and C4, and also several HLA genes possibly related to immune responsiveness.